Hardware
Types of Videoconferencing Systems:
There are two major classes of videoconferencing systems in use, desktop systems and room-size systems. Both systems use the same video signal, and differ mainly in the size of the audiences on both ends of the conference and the purpose of the event.
Desktop Video: Desktop video refers to systems based on a desktop computer system in which a small camera is mounted on top of the monitor of the computer system, and the software to allow image display, voice transmission, and other functions of the system resides in the computer. They are designed for one-on-one interaction, but can accommodate two or three people on each station if necessary. Desktop systems also include software for sharing control of programs, documents and other files, and are designed to facilitate collaboration.
Room-size Video: A room-size system is also based typically on a microcomputer system, with the video display projected through one or two large (27" or larger) monitors, or through a digital video projector for screen or wall display. They are designed for visibility and interaction of larger groups of people, such as a classroom of 30 students or a meeting of 12 people. Often, such a system includes microphones set in the middle of a table designed to pick up voices from anywhere around the table. In a classroom setting, demonstration and presentation tools such as overhead projectors and electronic blackboards are used to support typical instructional settings, and may include a microphone for each participating student.
State Frameworks
Most of the states in the Northwest region either have developed or are in some stage of considering telecommunication network systems for statewide access to two-way video and the Internet by schools. These systems are each designed to provide specific levels of services defined by:
- Capacity
- Transmission Standards
- Hardware Standards
- Software Standards
- Applications
- Geographical Coverage
- Local Responsibility
The first step in deciding among the options for a video system for a school or district is to determine what type of statewide system applies to your area, if any. In some cases, funding and/or other support is available. In all cases, there is some requirement for local responsibility. For example, the state system might deliver a cable to one site in a district and the district must take it from there. In other cases, the state service extends only as far as regional connecting points. Your planning will differ depending on what your state offers. (See the NW State Information.) If you are not supported by a statewide system, then your planning process must be extended to choosing a commercial service provider to gain access to distant sites.
Telecommunications lines
To choose telecommunications lines, you must become familiar with the concept of bandwidth (see the Glossary). Briefly, bandwidth is the carrying capacity of the communications line. The bandwidth of the video signal governs the quality of video, particularly the degree to which motion is smooth. A general rule of thumb is that a picture involving movement begins to appear smooth at about 384K. The degree of smooth motion that is acceptable depends on how accurate the motion must appear. Typically, meetings and courses by video are acceptable at the 384K level. Desktop video can frequently be satisfactory at lower levels if the content is a document or other still subject.
Compatibility
Your choice of system should take into account the compatibility required to communicate with the other sites you wish to involve. Adherence to state standards will serve you well in the state, but communication on a wider basis outside your state, if desired, needs to be considered. The most common sets of standards are H.320 and H.323. A desktop system can communicate with a room-size system if they both observe the same transmission standards, or protocols.
See resources for Videoconferencing Equipment.
Joe Kitchens, Superintendent, Western Heights, OK and Rick Feutz, Technology Coordinator, Kent, WA.
Comments on Hardware Selection Issues:
Kitchens, Superintendent, discusses a comprehensive and integrated approach to technology including two-way video, and the value of standards:
"If we are thinking of extending our ability to reach our parents, it makes little sense to me that we put a telephone in every classroom, at a time when the PC industry is merging with the telephone industry which is converging with the TV industry. We actually can pull all of these important components together under one format."
"When we decided that we wanted to put a VHS tape system in and distribute video across our seven school sites, we priced a video tape solution and it was $278,000 just to do the high school. Then we priced a PC-based video streaming solution and it was $75,000, and it did the whole district. Well, there really wasn't any question about where the value was on that issue."
"When we looked at our IP-based videoconferencing, we asked why we wouldn't want an H.320 conferencing that is a proven standard versus H.323 that is an emerging standard for distance learning? Well, a 320 system costs you significant amounts in line charges to maintain, whereas for 323 systems, those same lines that have access to the Internet are also capable of providing your distance learning situation. In our school we've been able to quantitatively say we're saving $30,000 a year by looking at an IP-based videoconferencing solution versus a 320-conferencing system. We have a 30% cost saving with a 323 system versus a 320 system and we also do not have any excess line charges, so there really isn't any reason that we shouldn't explore putting in the 323."
Feutz, Technology Coordinator concerning the danger of focussing only on equipment, with insufficient resources for continued maintenance:
"My greatest fear in all of these large networks that we put in for videoconferencing or data network, is that we will create an environment that we can't support physically. I think if you take a look across the country you'll find that larger school districts initially, and probably small districts, are running into that right now, putting in networks that they physically can't support. By doing that, the vision of the ability for educators to be able to use this technology will be lost in the dollars and cents because good planning and good visioning wasn't done up front."